The NFL combine features a variety of drills, but what do they all mean? Next we're going to explain the 40-yard dash.

Everyone knows the premise of the 40-yard dash, the athlete tries to run 40 yards as fast as they can and impress with their speed, but the athlete's 40 time tells you a lot more than just their speed. It gives you a players acceleration as well, especially in shorter areas within the splits, like the 10 and 20-yard split.

For positions that require speed, teams will generally like to see the players run the 40-yard dash in the 4.2 to 4.5 range, anything over that and some questions will begin to arise about the players speed. One has to remember however, that timed speed and game speed aren't the same in instances like this.

The Jacksonville Jaguars second round pick in 2012, defensive end Andre Branch, ran the 40-yard dash in 4.7 seconds, which put him in the top five for his position. Seahawks first round pick Bruce Irvin had the top time for defensive ends in 2012 at 4.5 seconds.